Pneumatosis cystoides intestinalis mimicking colonic subepithelial tumors with spontaneous resolution after relocation from a high-altitude region: a case report

Abstract

Background

Pneumatosis cystoides intestinalis(PCI) is a relatively rare condition with a pathogenesis that remains incompletely understood. It is typically managed through conservative medical treatment, with surgical intervention considered when necessary. We report a case of PCI in which the lesions resolved spontaneously after diagnostic endoscopic submucosal dissection (ESD).

Case presentation

A 51-year-old female, who had resided long-term at high altitude, presented with persistent abdominal pain and increased bowel movements. Routine blood tests and biochemical profiles showed no significant abnormalities. Colonoscopy revealed multiple submucosal protrusions in the ascending colon, which firm on probing with biopsy forceps. Endoscopic ultrasound demonstrated hyperechoic with acoustic shadowing. In combination with findings from contrast-enhanced abdominal CT, ESD was performed to remove one of the larger protrusions. Pathological examination confirmed the diagnosis of PCI. More than two years later, follow-up colonoscopy and contrast-enhanced abdominal CT revealed complete resolution of the lesions. Notably, the patient had not received any treatment during this period, aside from a change in her place of residence.

Conclusions

This case illustrates a rare but clinically important presentation of colonic PCI mimickingfirm subepithelial lesions, with documented complete resolution on both colonoscopy and CT after relocation from a high-altitude region.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-026-04982-4.

Introduction

Pneumatosis cystoides intestinalis (PCI) is a relatively rare gastrointestinal disorder, with an incidence of only 0.03% and a male-to-female ratio ranging from 2.4:1 to 3:1 [1–3]. It is characterized by the presence of gas-filled cysts within the intestinal wall, involving the mucosa, submucosa, muscularis propria, and serosa. PCI is considered a benign condition, although its exact pathogenesis remains incompletely understood [4]. Conservative management is the mainstay of treatment. However, surgical intervention becomes necessary when complications arise that pose a significant threat to the patient’s health [5]. Notably, previous literature indicates that the rate of overtreatment with surgical procedures can be as high as 27% [6]. This article reports a case of PCI diagnosed through a multidisciplinary approach. The patient received no PCI-directed medical therapy or additional invasive interventions beyond the diagnostic endoscopic submucosal dissection(ESD), and follow-up after two years revealed complete spontaneous resolution of the intestinal gas cysts. The case is discussed in the context of relevant features documented in the existing literature.

Case report

A 51-year-old female presented in February 2023 with a complaint of vague abdominal discomfort accompanied by increased bowel frequency (3–4 times daily), passing loose, yellowish stools. Self-administered antibiotic therapy provided no relief. Subsequently, she underwent gastroscopy and colonoscopy at a local hospital. Gastroscopy revealed chronic atrophic gastritis with erosion. Colonoscopy findings indicated multiple submucosal elevations of undetermined nature in the ascending colon (Fig. 1). The lesions varied in size, were firm in consistency, and showed no significant morphological change upon insufflation or suction. Contrast-enhanced abdominal computed tomography (CT) showed multiple small, oval-shaped, air-density shadows within the submucosa of the ascending colon, observable in coronal, sagittal, and axial planes. The lesions had smooth margins and well-defined borders, with the largest measuring approximately 20 mm in length (Fig. 2a). For further diagnosis and treatment, the patient was referred to our hospital. A detailed inquiry into her medical history revealed no prior pulmonary diseases (such as asthma, chronic cough, interstitial lung disease, chronic obstructive pulmonary emphysema, etc.), no history of steroid use, chemotherapeutic agents, immunosuppressants, alpha-glucosidase inhibitors, biologics, long-term antibiotic use, or probiotics, and no history of constipation, intestinal obstruction, colonoscopy/barotrauma, trauma, or abdominal surgery. However, she had resided in the Tibet region (altitude > 4000 m) for 17 years. The patient’s vital signs (temperature, heart rate, blood pressure, and respiration) remained stable. No abdominal tenderness, muscle guarding, or rebound tenderness was observed. Further investigations, including white blood cell count, hemoglobin count, C-reactive protein(CRP), lactate, albumin, liver and kidney function, coagulation profile, tumor markers, immune function, antinuclear antibody panel, and anti-neutrophil and basement membrane antibodies, showed no significant abnormalities. A chest CT revealed no signs of obstructive emphysema and no other significant abnormalities. Endoscopic ultrasonography (EUS) using a mini-probe demonstrated hyperechoic with acoustic shadowing (due to gas) located in the submucosal layer (Fig. 3). Although CT and EUS suggested gas-containing submucosal cysts, the unusually firm endoscopic appearance and lack of collapse with insufflation/suction raised concern for a subepithelial neoplasm. Standard endoscopic biopsy or fine-needle aspiration was considered unlikely to provide sufficient tissue to definitively exclude a submucosal tumor(SMT) such as a gastrointestinal stromal tumor or neuroendocrine tumor. Therefore, diagnostic resection of one representative lesion was performed via ESD after multidisciplinary discussion and informed consent. Histopathological examination of the resected specimen revealed multiple cystic spaces lined by fibrous stroma with mild inflammatory cell infiltration (Fig. 4). The histopathological diagnosis was PCI, consistent with the findings of contrast-enhanced abdominal CT. Considering the patient’s mild symptoms, absence of complications (such as obstruction or perforation), and her recent relocation to a low-altitude region, no PCI-directed medical therapy or additional invasive interventions were administered beyond the diagnostic ESD. Regular follow-up was recommended. Follow-up of the patient’s clinical status revealed significant improvement in abdominal pain, with bowel frequency gradually decreasing to 1–2 times per day and soft stool consistency. Notably, a follow-up colonoscopy in October 2025 demonstrated complete resolution of the colonic submucosal elevations (Fig. 5). A follow-up contrast-enhanced abdominal CT scan showed no significant bowel dilation or evidence of intramural masses in coronal, sagittal, or axial views (Fig. 2b).

Fig. 1.

a-b: Colonoscopy revealing multiple elevated lesions in the ascending colon (White arrow)

Fig. 2.

a: Contrast-enhanced abdominal CT findings. Axial, coronal, and sagittal views demonstrate multiple, small, oval-shaped gas-density cysts with smooth and well-defined margins within the submucosa of the ascending colon, the largest measuring approximately 20.1 mm. b: Follow-up contrast-enhanced abdominal CT. Axial, coronal, and sagittal views (same projections as in Fig 2a) demonstrate no significant bowel dilation or evidence of intramural masses. (Pre- and post-comparison lesions are marked with blue circles and squares.)

Fig. 3.

Mini-probe endoscopic ultrasonography showing an hyperechoic with acoustic shadowing submucosal-originating lesion(White arrow)

Fig. 4.

Photomicrograph of the resected specimen demonstrating multiple empty cystic spaces, with scant fibrous stroma and mild inflammatory cell infiltration (Red arrow) (H&E staining)

Fig. 5.

a-b: Follow-up colonoscopy showing a normal ascending colon without any mucosal elevations

Discussion and conclusions

Endoscopically, PCI lesions typically appear as soft, translucent, dome-shaped structures that may collapse upon puncture, most commonly affecting the colon and small intestine. However, some cases of PCI may be easily misdiagnosed under white-light endoscopy due to their resemblance to intestinal polyps and submucosal elevations; therefore, EUS and CT have important adjunctive diagnostic value for PCI [7–9]. In this reported case, the lesions in the ascending colon presented as multiple, firm elevations that did not change noticeably with insufflation or suction, necessitating differentiation from submucosal tumors. The diagnosis was established by integrating the findings from contrast-enhanced abdominal CT and the histopathological confirmation following ESD of one lesion.

In recent years, the proposed pathogenic mechanisms for PCI primarily include [10, 11]: (1) The mechanical pressure theory, involving both intraluminal and intra-alveolar pressure. Elevated intraluminal pressure may force gas through a breach in the mucosa into the bowel wall. This patient had resided long-term in a high-altitude area with low atmospheric pressure prior to diagnosis, a factor potentially associated with the development of PCI, consistent with previous literature reporting an association between high altitude and PCI [12, 13]. (2) The bacterial gas production theory. Diverse gut microbiota may produce gas that enters the intestinal wall layers through mucosal defects. (3) Immunological factors. In autoimmune diseases, inflammation, atrophy, degeneration, and fibrosis of smooth muscle cells in the gastrointestinal wall can slow motility. This may promote bacterial overgrowth and intestinal distension, facilitating gas entry into the bowel wall, while intestinal inflammation can damage the mucosal barrier. Additionally, factors such as diet and medications can influence the intestinal milieu (e.g., acid-base balance), contributing to the pathogenesis of PCI [14].

There is no standardized treatment protocol for PCI. Management strategies should be individualized based on clinical manifestations and any underlying conditions. Many cases resolve spontaneously, and asymptomatic patients require no treatment [15]. For symptomatic patients, conservative medical management is the first-line non-surgical approach, including antibiotics, regulation of gut microbiota and and hyperbaric oxygen therapy/oxygen therapy, or spontaneous resolution [11, 16–19]. Minimally invasive endoscopic interventions, such as high-frequency electrosurgical resection, biopsy forceps rupture, or needle aspiration for decompression, are feasible [20–22]. Surgical intervention is reserved for emergencies. However, it is noteworthy that patients presenting with hemodynamic instability, peritoneal signs, sepsis/shock, elevated lactate, leukocytosis, metabolic acidosis, portal venous gas with associated clinical manifestations, bowel wall thickening, ascites, poor enhancement, mesenteric ischemia, obstruction, volvulus, or perforation must undergo immediate surgery [23, 24]. As shown above, although previous reports have indicated that PCI may mimic colonic polyps or present as firm submucosal nodules, the present case provides an additional unique observation: complete resolution of the lesions was documented by both colonoscopy and CT following relocation from a high-altitude region (as illustrated in Table 1).

Table 1.

Summary of prior PCI case reports and comparison with the present case

Prior report type	Key finding	How current case diers
PCI mimicking colonic polyps or SMT	EUS useful for diagnosis [7–9]	Current case had firm ascending colon lesions and long-term follow-up
PCI as firm subepithelial nodules	Endoscopic resection used diagnostically [20–22]	Current case used ESD and later showed spontaneous complete resolution
High-altitude PCI series	High-altitude association reported [12, 13]	Current case documents disappearance after relocation

The patient in this report had multiple, relatively large submucosal elevations in the ascending colon, After diagnosis of PCI, because the patient was hemodynamically stable with mild symptoms, no peritonitis, no obstruction/perforation, no ischemic signs on CT, and essentially normal laboratory findings, she met the criteria for conservative follow-up. Apart from her recent relocation to a low-altitude region, no PCI-directed medical therapy or additional invasive interventions were administered. The complete resolution observed after 2.5 years demonstrates a temporal association between relocation from a high-altitude area and subsequent lesion resolution, suggesting that environmental pressure and oxygen supply may have influenced the disease course; however, the possibility of spontaneous resolution independent of relocation cannot be excluded.

In conclusion, it is essential for endoscopists to be systematically knowledgeable about PCI. When evaluating firm submucosal elevations in the differential diagnosis, integrating clinical history with imaging findings can help avoid misdiagnosis and guide conservative management strategies in select cases.

This case report follows the CARE (CAse REport) guidelines for completeness and transparency of reporting. A completed CARE checklist is provided as supplementary material.

Authors’ contributions

Z.X.L.,and Z.S.conceived and designed the project. Z.Q., and C.Y.X. drafted the manuscript. F.S.F. provided guidance on the CT images. All authors read and approved the final manuscript.

Funding

This study was supported by the Research Fund of National Health Commission (No.WKJ-ZJ-2435) and the Zhejiang Provincial Traditional Chinese Medicine Science and Technology Program Young Talent Project (No. 2021ZQ086).

Data availability

No datasets were generated or analysed during the current study.

Declarations

Ethics approval and consent to participate

Not applicable.

Consent for publication

We have obtained the patient’s consent and signed the patient consent. Acopy of the written consent is available for review from the Editor-in-Chief ofthis journal. The patient shared her perspective, stating that she was relieved by the non-surgical management and extremely satisfied with the complete resolution of her symptoms and lesions following her relocation to a lower altitude, without the need for further treatment.

Competing interests

The authors declare no competing interests.